When someone grows quickly, or puts on weight quickly, the tissue under the skin can be stretched quickly.

Collagen is the protein that holds the connective tissue together and it usually does a great job. But, in a sudden growth spurt, production of collagen may not be able to keep up in the dermis layer of skin.

As a result some people develop marks - lines - in the top layer of the skin, which we call stretch marks. These can start off being pink, purple, red or brown, but they fade over time often leaving a thin silvery line or they may no longer be visible. In the early stages you can feel a dent in the skin when you run your finger over a stretch mark.

The short answer is 'no'. Many people get some stretch marks, but a lot of people don't get any even if they are overweight or they grow quickly.

Your genes play a large part in whether or not you get stretch marks and even if you are slim, fit and healthy, and use lots of moisturisers and creams, you may still get them. Those moisturisers and creams can't help, the stretching happens under the top layer of the skin where the creams can't reach!

Over time the red or purple colour usually disappears until they become faint silvery lines, which are not so noticeable or they may become invisible.

Stretch marks will usually not fully go away again but if they worry you, you can make them less noticeable at the beach by:

wearing bathers that have 'boy legs'

wearing high front bathers like the Olympic swimmers do

wearing swimming shorts

wearing a 'rashie' (that also protects your upper body from the sun)

wearing a tee shirt over bathers at the beach

wearing jeans or pants that cover the hips and belly

not getting a sun tan. Stretch marks are more obvious if you have a tan, as they don't change colour (tan) while the skin around them does.

Now that people are aware of the dangers of sunbathing and the damage that the sun can do, you won't look any different from most other people in Australia when you cover up your skin. Skin cancer is far worse than stretch marks!

If you have stretch marks in a place that can be easily seen and you feel embarrassed about their appearance then you might use body make-up to cover them, or tanning creams or sprays may help. Be sure to follow the instructions carefully.

There are lots of creams and lotions around that say they can get rid of stretch marks but many are very expensive and they don't get rid of stretch marks.

Once you have finished growing and the stretch marks have faded you will hardly notice them.

However, if you feel really worried by the time you reach your 20's, then a dermatologist [skin doctor] or plastic surgeon may be able to reduce the appearance of your stretch marks. The techniques used are pretty expensive and it's a good idea to wait until your growing teen years are over.

Eating healthily, being active, taking care of your skin, staying out of the sun are all ways to take care of your body. Growing up can present you with lots of different challenges, but remember other people are facing those challenges too. Even the 'perfect' looking film stars and models have to face the same challenges as the rest of us, including, for some, stretch marks!

We've provided this information to help you to understand important things about staying healthy and happy. However, if you feel sick or unhappy, it is important to tell your mum or dad, a teacher or another grown-up.